JPA继承TABLE_PER_CLASS抛出MappableContainerException

Question

JPA继承有问题，服务器抛出错误。关于这个主题已经有很多问题，但是我找不到解决问题的方法，所以这里有关于我目前所拥有的细节......

超类：

@Entity
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
@DiscriminatorColumn(name = "PERSON_TYPE", discriminatorType = DiscriminatorType.INTEGER)
@Table(name = "PERSON")
public class Person {

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "TRIGGER_PERSON_PRIMARY_KEY")
    @SequenceGenerator(name = "TRIGGER_PERSON_PRIMARY_KEY", sequenceName = "PERSON_AI_SEQUENCE", allocationSize = 1, initialValue = 1)
    @Column(name = "PERSON_ID", updatable = false, unique = true, nullable = false)
    protected int personId;

子类：

@Entity
@Table(name = "APPLICANT")
@DiscriminatorValue(value = "1")
@PrimaryKeyJoinColumn(name="APPLICANT_ID")
public class Applicant extends Person {
}

错误消息：

The exception contained within MappableContainerException could not be mapped to a response, re-throwing to the HTTP container

Caused by: java.lang.ClassCastException: org.hibernate.mapping.UnionSubclass cannot be cast to org.hibernate.mapping.RootClass

Answer 1

super 类和 sub 类中不能有@Id。

<强>解决方案

从子类@Id

中删除Applicant

更多信息：

1. Spring 3.1 Hibernate 4 exception for Inheritance [cannot be cast to org.hibernate.mapping.RootClass]
2. Java/Hibernate JPA: InheritanceType.TABLE_PER_CLASS and IDs

Answer 2

我终于设法解决了这个问题。我采取了几个步骤：

1. 另一个扩展Person的类抛出错误，所以我修复了依赖。
2. 我已经将继承类型更改为JOINED，这实际上就是我正在寻找的 - 不同列的不同表和常用内容的一个根表。
3. 由于2.没有必要保留@PrimaryKeyJoinColumn。